Connector

ABSTRACT

In a plug-in connection ( 1 ), in particular for fluid lines, which comprises a part of the connection ( 2 ) to be inserted and a receiving part of the connection ( 3 ), between which a seal ( 10 ) can be clamped and which are able to be releasably connected to one another by flexible snap-in elements ( 7, 18 ) in a snap-in position, the seal ( 10 ) can, be clamped between a front portion ( 4 ) of the part of the connection ( 2 ) to be inserted and an abutment ( 11 ) in the receiving part of the connection ( 3 ) and the distance of the snap-in elements ( 7 ) of the part of the connection ( 2 ) to be inserted from the front portion ( 4 ) of the latter is dimensioned such that the snap-in position is reached after slight axial compression, and if need be radial compression, of the flexible seal ( 10 ).

FIELD AND BACKGROUND OF THE INVENTION

The invention concerns a plug-in connection, in particular for fluidlines, comprising a part of the connection to be inserted and areceiving part of the connection, between which a seal can be clampedand which are able to be releasably connected to one another by flexiblesnap-in elements in a snap-in position

Plug-in connections of this kind are known from practice in a widevariety of forms. To simplify the joining together of plug-inconnections, a snap-in connection with resiliently snap-engaging holdingelements, which correspond in pairs on the part of the connection to beinserted (“male” part) and on the receiving part of the connection(“female” part), is usually provided. Normally, flexible snap-in hooksor the like are provided on the receiving part, while the outer contourof the part to be inserted is provided with a step-shaped collar orannular collar, which serves as an abutment for the radially inwardlydirected snap-in hooks. At the same time as the joining together, thenecessary sealing of such a plug-in connection is ensured by a seal(sealing ring, flat gasket or the like) coming to bear on both sides,even before snap-in engagement of the holding elements, and possiblybeing compressed radially, at least slightly, before the snap-inposition is reached. This achieves radial prestressing of the seal,which prevents any escape of a fluid flowing via the plug-in connectionand/or the entry of foreign substances (air, contaminants) into theconnected line. Depending on the mechanical loading of the plug-inconnection by external forces such as tension/bending or by internalcompressive forces in the case of fluidic plug-in connections, thesnap-in connection must be very secure. This sometimes gives rise toproblems when separating the connection, manual disassembly withouttools always been preferable. The part of the connection to be insertedis often provided on its front outer circumference with a bevel, whichassists its introduction into the receiving part.

SUMMARY OF THE INVENTION

The invention is based on the object of specifying a simple plug-inconnection with an improved sealing effect.

accordingly to the invention, the seal can be clamped between a frontregion of the part of the connection to be inserted and an abutment inthe receiving part of the connection. At the same time, the distance ofthe snap-in elements of the part of the connection to be inserted fromthe front region of the latter is dimensioned such that the snap-inposition can be reached just by slight compression of the seal in theaxial direction. This has the advantage that the effective insidediameter of the seal, and consequently also the surface area subjectedto internal pressure, is smaller than in the case of a seal which bearsonly radially on the outside against the part to be inserted, while itsend face is completely free. If at least one portion of the seal is inbearing contact between the outer circumferential surface of the frontregion of the part of the connection to be inserted and the innercircumference of the receiving part of the connection, the connection isless sensitive to slight deviations from the alignment of the two partsof the connection, which may arise for example due to external forceeffects. The above advantageous effect is achieved in a particularlyexpedient way if the seal is of an annular design with an unround crosssection and with an inside diameter that changes over its axial extent,a portion with a greater inside diameter bearing against the outercircumferential surface of the part of the connection to be inserted.This form has the effect that, toward the part to be inserted, the mouthof the seal forms a funnel contour, which makes it easier for said partto be introduced. The radially drawn-in portion then lies in front ofthe front end of the part of the connection and forms the axial seal.The seal could be arranged and fastened on the front region of the partto be inserted. It is more expedient, however, because it is betterprotected against damage before and during the joining together of theplug-in connection, if the seal is fastened in the interior space of thereceiving part. The introduction and bringing into contact of the partof the connection to be introduced is made very much easier and the sealremains largely protected from damage if the front outer region, or thefront circumferential surface, of the part of the connection to beinserted is provided in a way known per se with a bevel or chamfer. Whenthe chamfered circumferential surface is in contact with the seal and iscompressing the latter both in the axial direction and in the radialdirection, on the one hand particularly good sealing quality isachieved, on the other hand the necessary joining force is reduced bythe wedging effect. A major advantage with regard to quality assuranceis achieved if a stop that limits the insertion depth of the part of theconnection to be inserted and acts independently of the snap-in meansand the seal is provided. Then the part of the connection can be pushedin at most to a fixed depth, the snap-in position already having beenreached before this. Inadvertent pinching of the flexible seal isreliably prevented in this way. Of course, such a stop could be providedon the receiving side, in the interior space, or be realized by anadditional component. In a particularly simple way, however, this stopis formed by at least one radial projection formed onto the part of theconnection to be inserted, for example an annular collar, the outer sizeof which is greater than the circular opening of the receiving part ofthe connection.

With regard to the internal bracing of the plug-in connection betweenthe seal and the snap-in elements, it is also of advantage if thesnap-in elements can be released from the snap-in engagement by means ofreleasing aids or lifting-out means that are separate or formed directlyon them. This makes the intentional separation of the plug-in connectionvery much easier. It also avoids damage being caused by improper use oftools and ensures that the parts of the connection can continue to beused after separation.

Production engineering advantages arise if the snap-in hooks and thelifting-out means are integrally formed onto the receiving part of theconnection; since all the parts of the plug-in connection are preferablyproduced from injection-moldable plastic, it is relatively easilypossible for such integral snap-in elements with releasing aids to beformed in an injection mold.

In a particularly expedient embodiment, the snap-in hooks and thelifting-out means are connected to the part of the connection via thinwebs and are designed as levers which can be flexibly pivoted bypressing in the lifting-out means and twisting the webs. With thisconfiguration, extremely economical use of material is possible, becausethe snap-in hooks and lifting-out means can be produced as componentparts of the outer wall of the receiving part of the connection and canbe easily punched free from said outer wall by slits.

A preferred use of these plug-in connections is for establishinglow-pressure hose connections in motor vehicles, for example forwindshield washing and/or windshield cleaning systems. They may also beused in systems of lines for pneumatic central locking systems or otherloads controlled by pressure or negative pressure.

The plug-in connection discussed here would also be suitable, however,for waterproof and pressuretight contacting of electrical conductors,which could be introduced for example along with the required endplug-in contacts into the interior hollow spaces of the parts of theconnection.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the subject matter of the inventionemerge from the drawings of an exemplary embodiment and the detaileddescription of the latter following below.

Represented in sectional form in the drawings:

FIG. 1 shows an adaptor, which is provided on one side as a receivingpart of the connection and on the other side as a part of the connectionto be inserted, as a combination of all the elements of the plug-inconnection,

FIG. 2 shows a part of the plug-in connection to be inserted and areceiving part of said connection, during joining together, and

FIG. 3 shows a joined-together plug-in connection in an enlarged view toillustrate the bearing contact of the seal and the function of thesnap-in elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

According to FIG. 1, a plug-in connection 1 respectively comprises apart of the connection 2 to be inserted (male part) and a receiving partof the connection 3 (female part), which are preferably bothrotationally symmetrical. The tubular part of the connection 2essentially comprises a front portion 4, a hollow-cylindrical shank 5and an annular collar 6 surrounding the shank. The front portion 4 hasthe same inside diameter as the shank, but its outer circumferentialsurface is essentially shaped as a truncated cone. Short cylindricalportions may be provided on both sides of the truncated cone. On its endedge, the outside diameter of the front portion 4 is smaller than thatof the shank 5 and increases continuously toward the shank, beyond thediameter of the latter. Thus, a bevel or chamfer is formed, making iteasier for the front portion 4 to be introduced into the correspondingreceiving part of the connection 3 (compare FIG. 2). At the transitionto the shank 5, a step 7 reduces the outside diameter of the frontportion from the maximum size to the somewhat smaller diameter of theshank 5. The step 7 forms one of the snap-in elements, the overallfunction of which is still to be discussed later.

In comparison with the part of the connection 2 to be inserted, thelikewise tubular receiving part of the connection 3 is of a morecomplicated construction. Its inside diameter corresponds essentially tothe maximum diameter of the front (frustoconical) portion 4. At adistance from an end opening 8, an annular seal 10 of elastomeric TPE(tetrapolyethylene) with an unround cross section has been fitted intothe interior space 9 of the part of the connection 3. Radially on theoutside, said seal bears against the hollow-cylindrical inner wall ofthe interior space 9. In the axial direction, it has been pushed againsta step 11 as an abutment, which reduces the diameter of the interiorspace 9 behind the seal to a size corresponding to the inside diameterof the part of the connection 2 to be inserted and prevents axialyielding of the seal 10 when the plug-in connection 1 is joinedtogether. Formed into the step 11, along its outer circumference, in theaxial direction is a channel or groove 12, into which an axiallyprojecting annular continuation 13 of the seal 10 has been pushed. Tosecure the seal 10 axially against falling out—during separation of theplug-in connection—also formed onto the outer circumference of saidseal, widening it, are two annular webs 14, which fall intocorresponding channels 15 in the inner wall of the part of theconnection 3 when the seal has been fully pushed in.

The inside diameter of the seal 10 narrows from a greater size, facingthe opening 8, to a smaller size, facing the step 11, doing so notcontinuously but in a short, step-like transitional region. On both itssides, the inner circumferential surfaces of the seal are approximatelyhollow-cylindrical, with different diameters.

Finally, further snap-in elements are provided in the outer wall of thereceiving part of the connection 3, preferably formed integrally ontothe part of the connection, which is injection-moulded from POM(polyoxymethylene). Two mutually opposite snap-in hooks 16, whichprotrude into the interior space 9, can be seen, having a flank 17 thatis oriented toward the opening 8 and runs obliquely with respect to thelongitudinal axis of the plug-in connection, and an end flank 18 that isoriented toward the step 11 and runs perpendicularly with respect to thelongitudinal axis. The snap-in hooks 16, each connected to the part ofthe connection 3 via a thin web 19, are punched free from the remainingouter wall by longitudinal slits 20 extending between the respective web19 and the end flank 18, so that they can spring in and out resilientlyin the radial direction. Lifting-out means 21 have been formed on,likewise punched free by slits, on the far side of webs 19 as releasingimplements. The snap-in hooks 16 and the lifting-out means 21 thus formtwo-armed levers or rockers with a pivot axis lying in the region of therespective web.

For further functional explanation, a joined-together plug-in connectionis explained with reference to FIG. 3. Identical reference numeralsidentify the elements of the drawing already introduced above. The linesadjoining the parts of the connection 2 and 3 on both sides (for examplehoses, pipes, cables) and the corresponding connecting means forestablishing the connection are not represented, because they are notrelevant to the actual connection.

In the enlarged representation according to FIG. 3 it can be seen thatthe end flanks 18 of the snap-in hooks 16 on the part of the connection3 have fallen in behind the step 7 between the front portion 4 and theshank 6 of the part of the connection 2. During joining together of theplug-in connection 1, they must temporarily spring out while twistingthe webs 19. It can also be seen that the seal 10 has come to bear flatagainst the frustoconical front portion 4 of the fully introduced partof the connection 2. However, the front edge of the portion 4 does notcome to bear against the step 11. It cannot run up against it even ifexcessive joining force is applied, because before that the annularcollar 6 would run up against the outer edge of the circular opening 8.Consequently, the seal 10 is effectively protected against inadvertentpinching. It cannot yield axially, because it is pushed against the step11. With respect to the function of the annular collar, it should benoted that this can also be realized by at least one radially protrudingprojection, which does not have to extend over the entire circumference.However, two or more mutually opposite projections should expediently beprovided.

In the joined-together position, the seal 10 is compressed in both theaxial direction and the radial direction, so that on the one hand aradial elastic force component is produced for the mutual sealing of thecircumferential surfaces and on the other hand an axial elastic forcecomponent is produced for sealing between the step 11 and the radialelement of the surface area of the front portion 4 projected in theaxial direction. The resultant significant increase in force duringjoining together on the one hand provides a perceptible indication backto a fitter that the end position of the part of the connection to beinserted has been reached, on the other it brings about constantprestressing against the snap-in elements, so that a particularly secureconnection that is free from backlash is ensured. To a slight extent,the seal 10 also compensates in its elastic deformation for dimensionaldeviations of the parts of the connection or snap-in elements.

Finally, it can be seen that, because of the stepped cross-sectionalconstriction of the inside diameter of the seal 10, two separate contactareas form between the seal and the frustoconical portion 4. As aresult, particularly high, surface pressure, providing effectivesealing, is produced in these regions. However, because of the wedgingeffect of the frustoconical front portion 4, the joining together of theplug-in connection 1 is possible with less force than if the seal 10were to be compressed purely axially by the end face of the part to beinserted, as known in the case of connections secured by screws (with aunion nut or the like), with their very much higher joining forces.

The elastomeric material to be displaced during compression of the seal10 can on the one hand enter the region between the two annular contactareas, on the other hand enter the separating joint between the end faceof the portion 4 and the step 11. The latter separating joint isconsequently largely filled, so that flow resistances caused by vorticesoccurring here can be minimized. By suitable shaping of the seal in thecontact region with respect to the step 11, the separating joint can becompletely filled, if need be, and thus an entirely smooth transitionfrom the part of the connection to be inserted to the receiving part ofthe connection can be created. The entry of the annular continuation 13into the groove 12 has the effect of forming a labyrinth arrangement onthe end face of the seal 10, at the step 11, which likewise represents ahigh degree of security against leaks.

For releasing the snap-in engagement or separating the plug-inconnection 1 it is sufficient to apply a pressure radially inward to thelifting-out means 21 that can be exerted for example with the thumb andindex finger of one hand. The lifting-out means 21 then temporarilyenter the interior space 9 of the part of the connection 3 or theremaining annular gap between the shank 6 and the inner wall of the partof the connection 3. The webs 19, which are preferably respectivelyarranged on both sides of the snap-in hooks or lifting-out means, areflex listed. As a consequence, the snap-in hooks 16 pivot radiallyoutward, and the end flanks 18 release the step 7, so that the part ofthe connection 2 can be pulled out without effort and without the use ofa tool. It goes without saying that the torsional rigidity of the websis to be less than the flexural rigidity of the snap-in hooks andlifting-out means.

List of Designations

1. plug-in connection

2. part of the connection to be inserted

3. receiving part of the connection

4. front portion (truncated cone)

5. hollow-cylindrical shank

6. annular collar

7. step

8. end opening

9. interior space

10. annular seal

11. step

12. groove

13. annular continuation

14. annular web

15. channels

16. snap-in hooks

17. flank

18. end flank

19. web

20. longitudinal slit

21. lifting-out means

We claim:
 1. A plug-in connection (1), in particular for fluid lines,comprising a part of the connection (2) to be inserted and a receivingpart of the connection (3), between which a seal (10) can be clamped andwhich are able to be releasably connected to one another by flexiblesnap-in elements (7, 18) in a snap-in position, wherein the seal (10) isclampable between a front portion (4) of the part of the connection (2)to be inserted and an abutment (11) in the receiving part of theconnection (3), wherein a circumference of the abutment is smaller thanan outer circumference of the insertable part of the connection forcompressing the seal in the axial direction of the connection uponinsertion of the insertable part into the receiving part of theconnection, and wherein the distance of the snap-in elements (7) of thepart of the connection (2) to be inserted from the front portion (4) ofthe latter and of the snap-in elements (16) of the receiving part of theconnection (3) from the seal (10) are dimensioned such that the snap-inposition can be reached after slight axial compression of the flexibleseal (10), and there is formed into said abutment (11) a groove (12),into which an axial continuation (13) of the seal (10) has been pushedfor forming a labyrinth system, wherein said seal is fastened in aninterior space of the receiving part of the connection, said seal ispushed in the radial direction, and in the axial direction against theabutment, and is secured against pulling out by radial form-fittingelements (14, 15).
 2. The plug-in connection as claimed in claim 1,wherein at least one portion of the seal (10) is clampable between anouter circumferential surface of the front portion (4) of the part ofthe connection (2) to be inserted and the inner circumference of thereceiving part of the connection (3).
 3. The plug-in connection asclaimed in claim 1, wherein the seal (10) is of an annular form with anunround cross section and with an inside diameter that changes over itsaxial extent, a portion with a greater inside diameter bearing radiallyon the outside against the front portion (4) of the part of theconnection (2) to be inserted.
 4. The plug-in connection as claimed inclaim 1, wherein a circumferential surface of the front portion (4) ofthe part of the connection (2) to be inserted is provided with a bevelor chamfer.
 5. The plug-in connection as claimed in claim 1, wherein achamfered circumferential surface of the front portion (4) of the partof the connection (2) to be inserted is in contact with the seal (10)and compresses the latter both in the axial direction and in the radialdirection.
 6. The plug-in connection as claimed in claim 1, wherein astop (6) that limits the insertion depth of the part of the connection(2) to be inserted into the receiving part of the connection (3) isprovided.
 7. The plug-in connection as claimed in claim 6, wherein thestop is formed by a projection formed onto the part of the connection tobe inserted, the outer size of which is greater than the opening (8) ofthe receiving part of the connection.
 8. The plug-in connection asclaimed in claim 1, wherein a snap-in element (step 7) which isgrippable from behind by snap-in elements (16, 18) of the receiving partof the connection (3) is provided on the front portion (4).
 9. Theplug-in connection as claimed in claim 1, wherein the snap-in elementsof the receiving part of the connection (3) are formed as flexiblesnap-in hooks (16) with an end flank (18) which, in the snap-inposition, grips behind a snap-in element (7) of the part of theconnection (2) to be inserted.
 10. The plug-in connection as claimed inclaim 9, wherein the snap-in hooks (16) or their end flanks can bereleased manually from the snap-in engagement by lifting-out means (21).11. The plug-in connection as claimed in claim 10, wherein said snap-inhooks (16) and said lifting-out means (21) are integrally formed ontothe receiving part of the connection (3).
 12. The plug-in connection asclaimed in claim 10, wherein the snap-in hooks (16) and the lifting-outmeans (21) are connected to the part of the connection (3) via thin webs(19) and are formed as two-armed levers which can be flexibly pivoted bypressing in the lifting-out means (21) and twisting the webs (19). 13.The plug-in connection as claimed in claim 11, wherein the snap-in hooks(16) and the lifting-out means (21) are connected to the part of theconnection (3) via thin webs (19) and are formed as two-armed leverswhich can be flexibly pivoted by pressing in the lifting-out means (21)and twisting the webs (19).
 14. The plug-in connection as claimed inclaim 2, wherein the seal (10) is of an annular form with an unroundcross section and with an inside diameter that changes over its axialextent, a portion with a greater inside diameter bearing radially on theoutside against the front portion (4) of the part of the connection (2)to be inserted.
 15. The plug-in connection as claimed in claim 1,further comprising a shank (5) connected at a first end to the frontportion (4) and an annular stop (6) extending around an end of saidshank (5) opposite the connection to the front portion (4).
 16. Theplug-in connection as claimed in claim 15, wherein said shank (5) is ahollow cylinder having an internal diameter substantially equal to aninternal diameter of said front portion (4).
 17. The plug-in connectionas claimed in claim 16, wherein said front portion (4) has an outerdiameter smaller than an outer diameter of said shank (5) at an endopposite the connection to the shank (5), said diameter of said frontportion (4) increasing gradually along a length of said front portion(4) towards the connection to said shank (5) to a diameter larger thanthe outer diameter of the shank (5).
 18. A plug-in connection, suitablefor a fluid line, comprising an insertable part of the connection and areceiving part of the connection, between which a flexible seal isclamped and which are able to be releasably connected to one another byflexible snap-in elements in a snap-in position, wherein the seal isclamped between a front portion of the insertable part of the connectionand a step in the receiving part of the connection, and wherein thedistance of the snap-in elements of the insertable part of theconnection from the front portion of the latter and of the snap-inelements of the receiving part of the connection from the seal aredimensioned such that the snap-in position can be reached after slightaxial compression of the seal; and there is formed into said step (11) agroove (12), into which an axial annular continuation (13) of the seal(10) has been pushed for forming a labyrinth system.
 19. A plug-inconnection, suitable for a fluid line, comprising an insertable part ofthe connection and a receiving part of the connection, between which aflexible seal is clamped and which are able to be releasably connectedto one another by flexible snap-in elements in a snap-in position,wherein the seal is clamped between a front portion of the insertablepart of the connection and an abutment in the receiving part of theconnection, wherein a circumference of the abutment is smaller than anouter circumference of the insertable part of the connection forcompressing the seal in the axial direction of the connection uponinsertion of the insertable part into the receiving part of theconnection, and wherein the distance of the snap-in elements of theinsertable part of the connection from the front portion of the latterand of the snap-in elements of the receiving part of the connection fromthe seal are dimensioned such that the snap-in position can be reachedafter slight axial compression of the seal; and wherein said seal isfastened in an interior space of the receiving part of the connection,said seal is pushed by the front portion of the insertable part of theconnection in the radial direction towards a circumferential surface ofthe receiving part of the connection and in the axial direction againstthe abutment of the receiving part of the connection, a groove isdisposed in a radially extending wall of the abutment and radialform-fitting elements are disposed circumferentially of the seal in thereceiving part of the connection, said seal being pushed into saidgroove and said form-fitting elements by the front portion of theinsertable part of the connection.